The letters stand for: coloboma of the eye, heart defects, atresia of the nasal choanae, retardation of growth and/or development, genital and/or urinary abnormalities, and ear abnormalities and deafness. CHARGE syndrome, a term that came into use as an acronym for the set of unusual congenital features seen in a number of newborn children.Other ocular malformations that include coloboma or are related to it: Glaucoma, nystagmus, scotoma, or strabismus may also occur. Sometimes, the eye may be reduced in size, a condition called microphthalmia. Other conditions can be associated with a coloboma. Commonly posterior colobomata affect the inferior retina, with resultant deficit in the superior visual field. If, for example, only a small part of the iris is missing, the vision may be normal when a large part of the retina or (especially) optic nerve is missing, the vision may be poor. Visual effects may be mild to more severe depending on the size and location of the coloboma. The pupil cannot contract to a smaller size than pictured, but may still be able to dilate in low light. Signs and symptoms Iris coloboma in the right eye of a 10-month-old child.

The level of vision impairment of those with a coloboma can range from having no vision problems to being able to see only light or dark, depending on the position and extent of the coloboma (or colobomata if more than one is present). Most cases of coloboma affect only the iris. A coloboma can occur in one eye (unilateral) or both eyes (bilateral). The classical description in medical literature is of a keyhole-shaped defect. Ocular coloboma is relatively uncommon, affecting less than one in every 10,000 births. The hole is present from birth and can be caused when a gap called the choroid fissure, which is present during early stages of prenatal development, fails to close up completely before a child is born. A coloboma (from the Greek κολόβωμα, meaning defect) is a hole in one of the structures of the eye, such as the iris, retina, choroid, or optic disc.

Deformed eye pupil